Changes between Version 20 and Version 21 of CodingRules

Timestamp:

11/29/13 10:30:21 (11 years ago)

Author:

tbretz

Comment:

--

CodingRules

@@ -112 +112 @@
 
 
+== ROOT ==
+
+Root is sometimes a bit tricky... here are a few coding rules or hints.
+
+0. Try to avoid using global pointers (gRandom is an exception)
+0. *same* is TGraphs is done by omitting the A (A means *with axis*)
+0. Try to avoid pointers, use objects, except if you add them to a root list.
+0. Histograms are usually automatically written to open files (it is switched of in the MARS code, but be carefull). Avoid that by removing the histogram from everything after creation: {{{hist.SetDirectory(0)}}}
+0. Make sure that all objects are properly deleted. E.g. when drawing something with DrawClone like {{{g=graph.DrawClone("AP")}}}, make sure you set the kCanDelete bit with {{{g->SetBit(kCanDelete)}}}. When you draw something with DrawCopy this is done automatically.
+0. Sometimes graphs are not where they ought to be (usually when you use DrawClone). In this case, add a {{{gROOT->SetSelectedPad(0)}}} before you cd() into the pad you want the graph to appear. Alternatively you can create the Clone() first and add the clone to the pad with {{{gPad->GetListOfPrimitives(clone, draw_options)}}}
+
+
+=== FACT camera display ===
+
+{{{#!C++
+
+// Create a FACT camera with 
+MGeomCamFACT geom;
+
+// Create a display with 
+MHCamera h(geom);
+
+// Set value of pixel 0 with 
+h.SetBinContent(1); // (note the +1!)
+
+// Enable the display of the pixel with 
+h.SetUsed(0) 
+
+// Or enable the the display of all pixels with 
+h.SetAllUsed()
+
+// Draw display
+h.DrawCopy();
+}}}
+
+
+=== Reading a display ===
+
+{{{#!C++
+TFile file("filename.root");
+if (file.IsZombie())
+   return;
+
+MStatusArray arr;
+if (arr.Read()<=0)
+   return;
+
+TWhatever *ptr = arr.FindObjectInCanvas("CanvasName", "TWhatever", "ObjectName");
+if (!ptr)
+   return;
+}}}
 
 
 
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